I know that Manstein and Paulus exchanged liaison officers with Storch in December, when Hoth tried to join the surrounded 6th Army. So flying to Stalingrad and back with some passengers was possible.
There (if you register) is a picture of a Stroch evacuation wounded of 71.ID in Stalingrad, but before the 6th Army was surrounded (in Sep 1942):
http://www.wehrmacht-awards.com/foru...ersheim&page=2